Method of removing, purifying, and recovering oil from tin plate



June 10, 1930. 1 HOLDEN ET AL METHOD OF REMOVING, PURIFYING, AND HECOVERING OIL FROM TIN PLATE Filed 'June 15 192e 2 Sheets-Sheet l /mvu `June l0, 1930. 1,763,430

, PURIFYING, AND RECOVERING oIL FROM J. H. HOLDEN Er AL METHOD 0F REMOVING TIN PLATE Filed June l5. 1926 2 Sheets-Sheet 2 )Vtizesses oil and polished the plates.

tin 4,' they are engaged by a' second Patented'June 10, 1930 QUNITED sTATEs PATENT-"OFFICE JAMES H. HOLDEN, OE BEENTWOOD, THOMAS OBEIEN, or SHARON, AND JOSHUA o.'

WHTZELAND RUFUS E. ZIMMERMAN, OF PITTSBURGH, PENNSYLVANIA, .ASSIGN- t `ORS T0 AMRICAN SHEET AND TIN l y PLATE COMPANY, OE PITTSBURGH, `PENNSYL- VANIM Al CORPORATION OE NEW JERSEY METHOD OE EEMOVINQJPURIPYING, AND nEcovEEINe On. EEOM TIN PLATE ,Application mea June 15,

This invention vrelates tomethods of removing, purifying and recovering the oil from tin plates `after they are tinned, and more particularly to a novel method in which the oil is removed from the plates and purified andxthen returned for use in the tin ot. l y p Heretofore the freshly tinned plates have generally been passed from the tin pot through a brauner in which the plates were scoured with bran, which absorbed the This method was costly becauseof the large `quantities lof bran used, and also because the oil was lost.

The present method removes the oil by,

washing the plates in an alkaline water solution and forms an alkaline palm oil-in-` water emulsion, which emulsion yis then treated torecover a water-in-'palm oil emulsion, and this second emulsion is then treated to recover pure dry palmoil suitable to be returned to the tinpot ,for'usa lIn the drawings?"` 4j- Figures 1 vandi); combin yShcitf-a Sectional elevation of a tinninggnachine, washing machine, and brann'er-,as usedin carrying out the steps of this method@` l y Figure 3 is a sectional Asidelennition of the apparatus used to separatefand jrecoverthe oil from the emulsion discharged fromthe washer. f

In carrying out this invention, black or untinned plates are'fed into'the flux side of a tin pot A, `wheretheyaneegaged by a pair of feed 'rollsl 2-landpfed downwardly through a body of iiuxffand into the molten tin 4'. As the plates "arep fedthrough the pair of feed rolls 5 and fed through the Vopening 6 into the oil or exit side of the pot A.` As the plates enter the oil side of the tin pot A, they `engage the guide 7, and areturned upfeed-out rolls Sfwhich feed theplates out ofthe tin pot throu h a .body of palmoil 9 andalso squeeze oianysurplus tin. The plates pass from the rolls 8 into the bite of a pair of feed rolls 10` which feed the' plates upwardly so that they` will fall onto an inclined feed-table11iafrom which the tion 1n the vat or tank C,

`the* lower roll of the 192e. Serial No. 1ie,1aq.

to have additions of soda ash or other alkali at the rate of four-tenths of a pound per hour.

The plates enter the vat or tank C from the table `11 through a pair of guides, 14:

and are engaged by pairs of scrubbing or scouring rolls 15 and 16. The lower roll of the pair of rolls 15 is of smaller diameter thanV the upper roll and has a fabric or rubber Surface covering 17, while the upper roll of the pair of rolls 16 is of smaller diameter than the lower roll and has a fabric or rubber surface covering 18. The smaller rolls of the pairs of rolls 15 and 16 are adapted to have a greater surface speed than the larger rolls so that the smaller rolls will rub or scour the plates to wash olf the oil and forman emulsion of the oil and water.

Other pairs of rolls 19, 20and 21 are arranged above the level of the washing soluand Serve to feed the washed plates from the tank and to squeeze olf and dry and also toy polish the plates. Y d Y The. lower roll of the pair of rolls 19, pair of rolls 20, and

the, upper roll of the each provided with a fabric or rubber surface covering 22, and the rolls of each of the above pairs of'rolls have a diiferential pair of rolls 21 are surface speed, so that the liquid from the A tank C will not only be squeezed oil:1 the plates but the rolls will have a rubbing action on theplates which Serves to dry the plates and also to polish the plates.

The plates may, 1f desired, be passed from the rolls 21 to stock as a finished article, but are preferably passed from the rolls 21 onto a conveyer-table 23, which conveys them to a brauner 24 of standard design, which is illed with a quantity of bran and has a series of pairs of rolls 25. The rolls of each of the pairs of rolls 25 have a differfoo plates, andI this scouring action together with the bran serves to remove any oil which might still remain on the plates and to highly olish the surfaces of the plates.

'.Fhe branner 24 is also provided with two pairs of feed-out rolls 26 which feed the polished plates onto a magnetic feed-out roll 27, which in turn delivers the plates onto a buggy 28 or the like, which will convey them to any suitable point such as to stock or a point of storage.

B washing the plates in the vat or tank t e oil is removed prior to the entrance the plates into the branner 24. Therefore, the bran may be .used for a considerable length of time in the branner, while heretofore the bran had to be continually cha This saving in the amount of bran used 1s a considerable item. v

The primary functionvof the washing of the plates in the vat or tank C is to rel move the oil from and clean the tin plate and to form an emulsion from which the oil may be recovered; but another and important result is accomplished at the same time, in that the oil is at least partlypuritied in the tank C. v The-oil removed from the Aplates in the vat or'tank C is emulsiied by the action of the scrubbing rolls 15 and 16 in the pres ence of the hot alkaline, solution. The oil is finely dispersed and thus put in an ideal condition for the removal of any impurities 'i soluble in the. alkaline kwash water. Other impurities, insoluble in water, may also be removed from the oil during emulsfication and sus nded in the water. The finely divided con ition of the oil is not lost until the oil is separated from the water as later described. The most harmful impurity in the oil is flux or zinc chlorid. It vis avery active t in causing the decomposition of palm oil, and experience has shownv that a f amountv olf-'the `zinc chloridis removed" from the oil'. prior rtoftheseparation of theoil from the water Yin thel emulsion formed inthe ltank C. V'lhefremovalof the zinc chlorid improves ythe'quality of the oil for` greatlyl tin t use;l lThe zinc chloride and other lsolu le compounds are washed from the oil l and dissolved in the water inthe tank C,

and are then carried by the water content of the emulsion and removed as. the Water is removedY from the emulsion.

At the same f time that the. chlorid and other soluble impurities are removed from the oil, quantities of the cleaning mixture or soda ash, dirt from the water supply, sodium salts, etc. are picked up by the oil. These added impurities are not objectionable, since they are easil l removed in the later centrifugal purificatwn step, to be described.

argev It will be noted from the above-that the I -from the tank C flows through an overflow-pi e 29 into a drain-pipe 30, thence to a trou 31, fromwhichy it flows through a pipe 3 to the heating and mixing chamber 33 of a treatment-tank-D.' The tank D is divided by transverse walls 34 and 35 into the heating and mixing chamber 33, a separating chamber 34" and an oil receiving chamber or sump 3.5. A A steam-line 36 extends intothe tank D, and has one branch .37 extending -onto and formi U a coil 38 on the inclined top face of t e wall 35, thence overand into. the mixing and heating chamber 33, as at 39, where it terminates and supplies live steam to the emulsion therein to heat and agitate the emulsion.v Another branch 40 of the steam-line v36 extends vdown into the oil chamber or sumpv 35a where 1it .terminates in a heating Coll 41. l

fn/acid-tank 45?.'V containingsulfuric acid is provided vabove thetank D, anda pump 43 is provided for" delivering measured quantities ofthe-acid through a conduit 44 to the heating and mixing chamber 33 of the tank D. f

The treatment tank D serves two purposes. It separates the ma'or portion of the water content from the o1l of the emulsion so that the water may be dumped or drained into drains or sewers without danger .of stoppage of the sewers and contamination of streams. It also permits for formation of a new emulsion in the form of a water-in-oil emulsion.l The treatment of the yalkaline vpalm'-.oil-.in-w'ater emulsion in the tank vD is continuous with a constant discharge of substantially oil-free water.

The emulsion entering the tank D has approximately the following composition:

Per cent Sodium carbonate..v 0.2 Palm oil 2.1 Water 97.7

The overflow orv water discharged from the tank D contains little or no oil, approxiof'sulfuric acid from Athrough the conduit 44 emulsion.'

'1,763,430 ence has shown that it is easily possible to plicated methods might be used. Acids other recover from 98 to v99 per cent. of the oil than .sulfuric may be used to break the oilfrom the emulsion entering thc tank As the emulsion flows into the chamber 33 of the treatment-tank D, a small quantity the tank 42 flows and mixes with the T'he quantity of sulfuric acid entering the oil-in-water emulsion in the chamber 33 of the treatment tank D is regulated so as to provide a concentration of approximately .0l per cent. in the water sep; arated out of. the emulsion in -the separating Vchamber 34a. Live steam is delivered into .thefmixture of acid and emulsion lin the chamber 33, from the pipe 39 which heats the mixture and accelerates the reaction, and also serves to thoroughly mix the emulsion and acid. The reaction of the acid and emulsion `is favored by high temperature `and good agitation. A temperature of 140 degrees Fahrenheit is enerally maintained in the chamber 33. T e effect of the acid is to break down the alkaline palm `oil-i11- water emulsion so that ,the water and oil may be readily separated. The quantity of emulsion and acid mixture builds up in thel chamber 33 and Hows over the wall 34 into the separating-chamber 34a where it is allowed to separate by gravity, the oil rising and the Water settling and being discharged through a stand-pipe arranged to mainltaina water level closely adjacent the top of the Wall 35 so that the oil rising to the top of the water will flow over the wall 35 into the oil chamberror sump 35a. The oil rising through the water of the broken down oil-'in-water emulsion .will pick up or combine with some of the Water and form a water-in-oil mixture. Experience has shown that-a water level approximately 1% inches below the top of the wall 35 is satisfactory.

The oil which rises to the surface in the separating chamber 34a as a water-in-oil mixture gradually builds up as a frothy mixture and after reaching a few inches in thickness overflows into the oil chamber or sump 35a. This flow is aided by the application of heat from the coil 38 on the `top of the wall 35. The oil-chamber or sump 35" is of sufficient capacity to permit a considerable accumulation of the water-in-oil mixture, and it is'not necessary that the subsequent operations be carried on continuously, although it is entirely possible to make the entire process continuous.

The results obtained by breaking down the emulsion with sulfuric acid and separating the oil from the water of the yemulsion may be accomplished by a number of other means, but probably less -efficiently. The treatment of the emulsion may be carried on entirely as a batch proposition,without continuous separation; also other more comin-water emulsion. Experience has `thus far shown that commercial sulfuric acid of 60 degrees Baume strength is the most economical to use. However, almost .any other acid oi' acid mixture, such as vwaste pickle liquor, may be used as reagents to break the emulsion. v

After the water-in-oil mixture has collected in the chamber or sump pumped out through a conduit 46 47 and discharged into a screen 48. The mixture flows through the screen 48 while any large particles of tin or other foreign matter remain on vthe screen. The waterin-oil mixture flowing through the screen is collected in a vat' 50 having a steam coil 5l therein. A pipe 52 leads from the vat 50 to a pump 53 which draws the mixture from the vat 50 and forces it through a coil 54 in a heating drum 55. The water-in-oil mixture is heated in the coil 54 so as to vaporize the water content thereof and' the coil discharges the oil and vapor mixture into the lower end of a stack 56. Steam is supplied to the drum 55 through an inlet pipe 7 at approximately 140 pounds per square inch pressure, and flows from the drum through a pipe 58 to a steam-trap or4 the lilnot shown).

The oil and vapor mixture discharged from the coil 54 into the stack 56 is separated, the vapor being picked upby the draft .of air in the stack and the oil flowing down into the storage-vats or tanks 59 and 60 which are coils to maintain the oil at approximately 300 degrees Fahrenheit. The heated oil from the tanks 59 and 60 is adapted to be passed through a pipe 61 to a standard form of centrifuge 62 and have the solid foreign matter separted 4therefrom. The finally purified oil is then discharged into a tank or vat 63 and is ready to be returned in any desired manner to the tin pot A for use'on other tin plate.

The water-in-oil mixture pumped 'from the sump 35a contains a large amount of water, some sulfate picked up in the treatby va pump ment-tank D,'and incidental dirt and for e1gn matter picked up at various stages in the process. Notwithstanding the increase of certain impurities, an important step in the purification has taken place inthev removal of the large amount of chlorid by the washing fluid. The chlorid is not readily removed in the subsequent operations, while the other impurities are removed more or less completely after the oil is dried.

As the water-in-oil mixture is discharged on the screen 48 any large particles of foreign matter are removed-. The screened mlxture is then vcollected in the vat 50 and provided with steam-V the oil side of.r

35a, it is p reheated by the steam coil 51. The preheated mixture is then pum d from the -vat 50 and forced through t e coil '54 in ture is vaporized in the passage of the mixp pot oil the moval a small rate of ow through the centrifuge ture through the coil 54 and the water vapor and oi are separated where the mixture of oil and water vapor is forced into thev of air in the stack 56, thus up-flowing draft The vapor will be carried drying the oil.

w 'le the dried oil will run down through the stack and be collected in the tank or vat 59. Bailles and additional heat may be yused in the stack if desired or necessary.

By a proper control of temperature, air flow and pumping of the water-in-oil mixture, the water passes up the stack 56 as steam or vapor, and only a trace or less than 0.1 ,per

cent. of water remains in the oil. Experience has shown that the whole operation yexit end of the drier-coil 54. If this temperature is maintained at 300` degrees Fahrenheit or above and there is a proper flow of air through the stack 56, the water will be removed practically completely.

The dried oil is passed from the tank or vat -60 through the high speed centrifuge 62. The centrifuge 62 serves to throw out a considerable proportion of the ash form- 'ing and other foreign matter from the oil` as a sludge, and lowers the viscosity of the dried o1l to approximately the same value as when it left the tin pot A. The oil returned to the tin pot contains a much smaller amount of chlorid and probably less ash and other foreign matter in eneral than the oil removed from the tin ptes in the washerl C.

The dried oil is fed to the centrifuge 62 at.

`a high temperature for eiiicient sludge re- This sludge removal is favored by and a hi h oil temperature. Experience has shown tat a temperature of approximately 300 degreees Fahrenheit and a fiow of forty gallons per hour is very eilicient.

In addition to the purification of the tin taking place in the centrifuge 62, a valuable by-product is obtained in the form of the slud e removed from the oil, which is deposite in the bowl of the centrifuge and recovered. This sludge is rethe water content of the mixture tok through the stack by the stack-draft,A

be controlled by the temperature at moved from the centri and taken to the scruif furnace of the mill where the tin content is overed as a tin-bearing ash, and the value of the tin thus recovered is sufficient to cover a large proportion of the expenses chargeable to this oil treating process. s

From the above, it will be readily understood that we have developed a complete process whereby the oil is removed from the tin plates, urified and recovered, with a minimum o expense and labor.

While we have shown and described certain specific apparatus used to carry out our rocess together with specific steps, it will e understoodthat we do n'ot wish to be limited to these details, since various other forms of apgiaratus may be used to carry out the steps o our novel method, and various modifications in the method steps may be made, such as changes in temperatures, rates of flow, and the like without in any way departing 'from the scope of our invention .as defined in the appended claims. We claim: i

, 1. The method of purifying and recovering palm oil from an alkaline palm oil-inwater emulsion formed b from tin plate and the like with an alkaline water solution, which consists in collecting the emulsion, breakin by addingv acid to said collected emulsion, separating the major portion of the water content of the broken down emulsion b gravity while the oil content of said emu sion rises through and floats on said water in the form lof water-in-oil mixture, then coly lecting said water-in-oil mixture, heating said water-in-oil mixture so as to vaporize the water content thereo then dischar fng the oil and water vapor mixture forme by vaporizing the water content of the waterin-oil mixture, into the path of a body of upowinggaseous fluid so. asl to' permit the water vaporstol be carried upwardl with the gaseous fluid while the loil falls tlivroughv Vsaid fluid by gravity substantially free from allA water, t env collecting` said oil, and finally separating all foreign solid inatter from said collected oil.

2. The method of'purifyin'g and recovering palm oil from an` alkaline palm oil-inwater emulsion formed by washing palm `oil from tin late and the like with an alkaline water so ution, which consists in collecting the emulsion, breakin down the emulsion by adding acid tol said collected emulsion, separating the ma'or portion of the water content of the bro en down emulsion byv gravity while the oil content of said emulsion rises through and floats on said water in the form of a water-in-oil mixture, then collecting said water-in-oil mixture, heatin said water-in-oil mixture so Aas to vaporize the water content thereof,

washing palm oill down the emulsion oil falls through said fluid then dischargin the oil and water vapor mixture forme by vaporizing the water content of the water-in-oil mixture into the ypath of a body of up-iiowing gaseous fluid so as to permit the water va upwardly with the gaseous fluid while the by gravity substantiall free from all water, then collectin sai oil, and finally centrifuging the oi to remove ash-forming materials, tin pairticles and other foreign matter from the o1 y v 3. The method of purifying and recovering palm oil from an alkaline palm oil-in- Water emulsion formed by washing palm oil from tin plate and the like with an alkaline water solution, which consists in collectin the emulsion, breaking down the emulsion by adding acid to said collected emulsion, separatin the major portion of rthe water content o the broken down emulsion by gravity while the oil content of said emulsion rises through and floats on said water in the form of a water-in-oil mixture', then collecting said water-in-oil mixture, heating said water-in-oil mixture so as to vaporize the water content thereof, then discharging the oil and water vapor mixture formed by vaporizing the water content of the water-in-oil mixture into the path of a body of up-lowing gaseous Huid so as to permit the water vapors to be carried upwardly with the aseous Huid while the oil falls through saiiluid by gravity substantially free from all water then collecting said oil, and 'finallylcentrifuging the oil to remove any ash-forming materials, tin particles and other foreign matter as a sludge, collecting the oil for reuse, and collectin the sludge to recover the tin content thereo In testimony whereof, I have hereunto signed my name.

JAMES H. HOLDEN.

whereof, I have .hereunto THOMAS OBRIEN.

In testimony signed my name.

In testimony signed my name.

JOSHUA C. WHETZEL. In testimony whereof, I have hereunto signed my name.

RUFUS E. ZIMMERMAN.

pors to be carried whereof, I have hereunto 

